opti621: use PCI clock value provided by controller

Use PCI clock value provided by controller instead of depending on
a default (or user supplied) value.

Based on a bugreport from Juergen Kosel & inspired by pata_opti.c code.

Tested-by: Juergen Kosel <juergen.kosel@gmx.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/pci/opti621.c

@@ -193,11 +193,10 @@ typedef struct pio_clocks_s {
 	int	recovery_time;	/* Recovery time (clocks) */
 } pio_clocks_t;
 
-static void compute_clocks(int pio, pio_clocks_t *clks)
+static void compute_clocks(int pio, pio_clocks_t *clks, int bus_speed)
 {
 	if (pio != PIO_NOT_EXIST) {
 		int adr_setup, data_pls;
-		int bus_speed = ide_pci_clk ? ide_pci_clk : system_bus_clock();
 
 		adr_setup = ide_pio_timings[pio].setup_time;
 		data_pls = ide_pio_timings[pio].active_time;
@@ -234,16 +233,34 @@ static void opti621_set_pio_mode(ide_drive_t *drive, const u8 pio)
 	u8 pio1 = 0, pio2 = 0;
 	pio_clocks_t first, second;
 	int ax, drdy;
-	u8 cycle1, cycle2, misc;
+	u8 cycle1, cycle2, misc, clk;
 	ide_hwif_t *hwif = HWIF(drive);
 
 	/* sets drive->drive_data for both drives */
 	compute_pios(drive, pio);
 	pio1 = hwif->drives[0].drive_data;
 	pio2 = hwif->drives[1].drive_data;
 
-	compute_clocks(pio1, &first);
-	compute_clocks(pio2, &second);
+	spin_lock_irqsave(&opti621_lock, flags);
+
+	reg_base = hwif->io_ports.data_addr;
+
+	/* allow Register-B */
+	outb(0xc0, reg_base + CNTRL_REG);
+	/* hmm, setupvic.exe does this ;-) */
+	outb(0xff, reg_base + 5);
+	/* if reads 0xff, adapter not exist? */
+	(void)inb(reg_base + CNTRL_REG);
+	/* if reads 0xc0, no interface exist? */
+	read_reg(CNTRL_REG);
+
+	/* check CLK speed */
+	clk = read_reg(STRAP_REG) & 1;
+
+	printk(KERN_INFO "%s: CLK = %d MHz\n", hwif->name, clk ? 25 : 33);
+
+	compute_clocks(pio1, &first,  clk ? 25 : 33);
+	compute_clocks(pio2, &second, clk ? 25 : 33);
 
 	/* ax = max(a1,a2) */
 	ax = (first.address_time < second.address_time) ? second.address_time : first.address_time;
@@ -266,21 +283,6 @@ static void opti621_set_pio_mode(ide_drive_t *drive, const u8 pio)
 		second.recovery_time, drdy);
 #endif
 
-	spin_lock_irqsave(&opti621_lock, flags);
-
-	reg_base = hwif->io_ports.data_addr;
-
-	/* allow Register-B */
-	outb(0xc0, reg_base + CNTRL_REG);
-	/* hmm, setupvic.exe does this ;-) */
-	outb(0xff, reg_base + 5);
-	/* if reads 0xff, adapter not exist? */
-	(void)inb(reg_base + CNTRL_REG);
-	/* if reads 0xc0, no interface exist? */
-	read_reg(CNTRL_REG);
-	/* read version, probably 0 */
-	read_reg(STRAP_REG);
-
 	/* program primary drive */
 	/* select Index-0 for Register-A */
 	write_reg(0, MISC_REG);